apheresis vs erasure

apheresis

noun
  • The removal of blood from a patient, and the removal of certain components (such as platelets) from that blood, followed by the transfusion of the filtered blood back to the donor (patient). 

  • Elision, suppression, or complete loss of a letter or sound (syllable) from the beginning of a word, such as the development of special from especial; procope. 

erasure

noun
  • The action of erasing; deletion; obliteration. 

  • The state of having been erased; total blankness. 

  • A tendency to ignore or conceal an element of society. 

  • The place where something has been erased. 

How often have the words apheresis and erasure occurred in a corpus of books? (source: Google Ngram Viewer )